/*******************************************************************************
    Copyright (c) 2014 IBM Corp.

    All rights reserved. This program and the accompanying materials
    are made available under the terms of the Eclipse Public License v1.0
    and Eclipse Distribution License v1.0 which accompany this distribution.

    The Eclipse Public License is available at
      http://www.eclipse.org/legal/epl-v10.html
    and the Eclipse Distribution License is available at
     http://www.eclipse.org/org/documents/edl-v10.php.

    Contributors:
      Ian Craggs - initial API and implementation and/or initial documentation
 *******************************************************************************/

#include "MQTTPacket.h"
#include "StackTrace.h"

#include <string.h>

/**
    Determines the length of the MQTT unsubscribe packet that would be produced using the supplied parameters
    @param count the number of topic filter strings in topicFilters
    @param topicFilters the array of topic filter strings to be used in the publish
    @return the length of buffer needed to contain the serialized version of the packet
*/
int MQTTSerialize_unsubscribeLength(int count, MQTTString topicFilters[]) {
    int i;
    int len = 2; /* packetid */

    for (i = 0; i < count; ++i) {
        len += 2 + MQTTstrlen(topicFilters[i]);    /* length + topic*/
    }
    return len;
}


/**
    Serializes the supplied unsubscribe data into the supplied buffer, ready for sending
    @param buf the raw buffer data, of the correct length determined by the remaining length field
    @param buflen the length in bytes of the data in the supplied buffer
    @param dup integer - the MQTT dup flag
    @param packetid integer - the MQTT packet identifier
    @param count - number of members in the topicFilters array
    @param topicFilters - array of topic filter names
    @return the length of the serialized data.  <= 0 indicates error
*/
int MQTTSerialize_unsubscribe(unsigned char* buf, int buflen, unsigned char dup, unsigned short packetid,
                              int count, MQTTString topicFilters[]) {
    unsigned char *ptr = buf;
    MQTTHeader header = {0};
    int rem_len = 0;
    int rc = -1;
    int i = 0;

    FUNC_ENTRY;
    if (MQTTPacket_len(rem_len = MQTTSerialize_unsubscribeLength(count, topicFilters)) > buflen) {
        rc = MQTTPACKET_BUFFER_TOO_SHORT;
        goto exit;
    }

    header.byte = 0;
    header.bits.type = UNSUBSCRIBE;
    header.bits.dup = dup;
    header.bits.qos = 1;
    writeChar(&ptr, header.byte); /* write header */

    ptr += MQTTPacket_encode(ptr, rem_len); /* write remaining length */;

    writeInt(&ptr, packetid);

    for (i = 0; i < count; ++i) {
        writeMQTTString(&ptr, topicFilters[i]);
    }

    rc = ptr - buf;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}


/**
    Deserializes the supplied (wire) buffer into unsuback data
    @param packetid returned integer - the MQTT packet identifier
    @param buf the raw buffer data, of the correct length determined by the remaining length field
    @param buflen the length in bytes of the data in the supplied buffer
    @return error code.  1 is success, 0 is failure
*/
int MQTTDeserialize_unsuback(unsigned short* packetid, unsigned char* buf, int buflen) {
    unsigned char type = 0;
    unsigned char dup = 0;
    int rc = 0;

    FUNC_ENTRY;
    rc = MQTTDeserialize_ack(&type, &dup, packetid, buf, buflen);
    if (type == UNSUBACK) {
        rc = 1;
    }
    FUNC_EXIT_RC(rc);
    return rc;
}


